This invention relates to an improved wheel casting, and the method of preparing the two-piece tire rim from the casting. More specifically, this invention relates to a molded, one-piece wheel casting, and the method of preparing from the one-piece casting a two-piece tire rim.
Heretofore it has been customary to manufacture certain types of tire rims from two separately molded parts or wheel castings, which are circular in configuration and are referred to as the inner and outer rim castings. After the two parts are separately molded they are bolted, welded or otherwise secured coaxially together to form a final, two-piece tire rim.
The major disadvantage of prior, two-piece tire rims of the type described is that it has been necessary to prepare and utilize two different molds, one to prepare the outer rim casting, and the other to prepare the inner rim casting. For each ultimate tire rim, therefore, there has to be made a different casting for each of the inner and outer rims, each casting requiring associated labor costs.
It is an object of this invention, therefore, to considerably reduce the number of molds and castings required to prepare two-piece tire rims of the typed described, and also to considerably reduce the associated labor costs.
To this end, it is an object of this invention to provide one mold for producing a single wheel casting which is ultimately divided into what become the inner and outer rims of a two-piece tire rim. More particularly, this invention relates also to a method of producing a novel wheel casting in a single mold, and subsequently machining the molded wheel into separate rims, inner and outer, respectively, which are then secured together to produce a two-piece tire rim of the type that formerly required the separate casting of two separate rim sections, the inner, and outer, respectively.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particular when read in conjunction with the accompanying drawings.
A molded, one-piece wheel casting which is generally cup-shaped in configuration, is open at one end, closed at its opposite end. The closed end of the casting has formed coaxially in its inner surface an inner annular recess facing the open end of said casting, and has formed coaxially in its outer peripheral surface an external annular recess radially spaced from and in axial registry with the internal annular recess. A two-piece tire rim is prepared by cutting through the closed end of the casting from the outer to the inner annular recess, thus separating the casting into generally annular and disc-shaped sections, respectively. The two sections are then separately machined and joined together to form a two-piece tire rim.